SAN FRANCISCO - Four technology companies, including Apple and Google, have resumed mediation talks with tech workers in a high-profile lawsuit over hiring practices in Silicon Valley, according to a court filing.

Plaintiffs accused Apple, Google, Intel and Adobe of conspiring to avoid poaching each other's employees. Last month, US District Judge Lucy Koh in San Jose, California rejected a proposed US$324.5 million (S$405.92 million) settlement in the class action case, saying it was too low.

In the court filing on Wednesday, both sides said they had resumed mediation with a retired judge but provided no additional details on the talks. They also asked Koh to set a new trial date.

An Apple spokeswoman declined to comment. Intel and Adobe also declined to comment. Representatives for the plaintiffs, along with Google, could not immediately be reached.

Tech employees alleged that the conspiracy limited their job mobility and, as a result, kept a lid on salaries. The case, filed in 2011, has been closely watched because of the possibility of big damages being awarded and for the opportunity of a glimpse into the world of some of America's elite tech firms.

Plaintiffs based their case largely on emails in which Apple's late co-founder, Steve Jobs, former Google Chief Executive Officer Eric Schmidt and some of their rivals hatched plans to avoid poaching each other's prized engineers.

In rejecting the proposed settlement, Koh cited "substantial and compelling evidence" that Jobs "was a, if not the, central figure in the alleged conspiracy." Given the strength of the case against the companies, the plaintiffs should have gotten more money, Koh wrote.

A hearing is scheduled for Sept. 10.

The case is In Re: High-Tech Employee Antitrust Litigation, US District Court, Northern District of California 11-cv-2509.